Snap switch



H. E. MALONE Feb. 8,1949.

SNAP SWITCH Filed May 4, 1945 INVEN TOR. A/OMEQE M/M o/vs' BY J42? M Patented Feb. 8, 1949 SNAP SWITCH Homer E. Malone, Milwaukee, Wis., assignor to Perle: Corporation, Milwaukee, Wis., a corporation of Wisconsin Application May 4, 1945, Serial No. 591,950

8 Claims. 1

This invention relates in general to switching mechanisms. and more particularly to enclosed snap switches for use in automatic control -devices.

It has become common to employ enclosed snap switch mechanisms in automatic controls such as thermostats, pressure controls, etc. These snap switches consist of a snap action contact mechanism mounted in a plastic housing, the switch being actuated by a plunger which extends through one wall of the housing. These switches also have terminals on the outside of the housing for attaching the lead wires to the control. In the snap switch mechanisms now in use, the terminals are located on the side of the switch opposite from the plunger. This arrangement is satisfactory for many applications of the switch in automatic control devices. However, this switching arrangement involves diiilculties in design when it is incorporated in many other types of control devices. In these devices-it is necessary to locate the switch so that the wiring terminals are accessible to the installer. In many' cases this position of the switch in the control involves diillculties in obtaining an actuating mechanism which reaches the switch plunger. Thus in certain applications the switch must be mounted on brackets spaced from the base, and additional mechanism, such as bell cranks, are required to transfer the motion from the condition responsive device to the switch plunger. These additional parts, in addition to increasing the expense oi the control, also decrease the sensitivity oi the control due to the additional friction which they cause. I

The primary object of the present invention is to provide a new type of snap switch mechanism which is especially adaptable-to automatic control devices.

In accordance with the present invention the snap switch mechanism is incorporat d in a generally rectangular shaped housing which is formed with a terminal panel that extends at an angle to both the base and side walls of the housing. This arrangement spaces the terminal panel from the base of the instrument upon which it is mounted and insures easy access to the terminals, regardless of the position of the switch in the control.

A further object of the invention is to provide an enclosed snap switch mechanism which is short in length. This increases the flexibility in application of the switch.

Other objects will appear as this description proceeds.

For a full disclosure of the invention, reference is made to the following description and to the accompanying drawings in which,

Fig. 1 is an external view in perspective of the new type snap switch mounted on a suitable support;

Fig. 2 is a view of the switch housing similar to that shown in Fig. 1, with the support and with wall portions of the housing broken away to better illustrate the construction thereof;

Fig. 3 is a sectional view taken on line 83 of Fig. 1 with the contacts shown in open position;

Fig. 4 is a sectional view taken on line 4-4 of Fig.

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4; and

Fig. 6 is a view in perspective of the bell crank supporting bracket; and

, Fig. 7 is a view in perspective of the bell crank lever. I

. Referring to Fig. 1, reference character I indicates the switch housing which is generally rectangular in form but which is formed with an angular face 2 disposed in obtuse angle forming relation with respect to the vertical and horizontal wall portions joined therewith. This angular face provides a terminal panel for the switch, this terminal panel including terminal screws 3 and 4. Preferably the terminal panel is formed with a barrier 5 between the terminal screws and with barriers 8 and 7 at the end oi the housing. The housing illustrated is shown of two-piece construction. including housing members 8 and 9. The housing member 8 forms a base member for the switch and is L-shaped. This base member at its ends is formed with upstanding bosses i0 and -Il having mounting holes i2 and I3. These mounting holes provide for mounting the switch on a suitable support it by means oi screws i8.

The housing member 9 is also L-shaped with an angular corner wall forming the terminal panel- This housing member is also formed with end walls I6 and ii. The housing members are 3 minal screw 3 fits into a similar insert or bushing (as shown) and is attached to a bracket 23 which receives a contact stud 24. The terminal screws are thus directly connected by brackets 2| and 23 with the stationary contacts 22 and 24.

The stationary contacts cooperate with movable contacts 25 and 28. The contact 25 is directly secured to a contact bar 21. Contact 28 is attached to a leaf spring 28, the other end of this spring being secured to contact bar 21 at contact 25.

The contact bar 21 is provided with cars 28 (Fig. 4) which receive a pivot pin 30. This pivot pin is supported between ears 3| of a bell crank member 32. This bell crank member is formed with an armature portion 33 which is located adjacent a permanent magnet 34. The bell crank member 32 is also formed with ears 35 which receive a pivot pin 36 which is supported by ears 31 of a bracket member 38. This bracket member is supported at the back of the terminal panel by means of a screw 39 which extends through the panel. The bracket 38 is formed with a downwardly extending portion 40 which engages the stationary magnet. The bracket 38 thus serves the dual function of supporting the bell crank 32 and holding the permanent magnet in place.

The base member 8 is formed with an opening for receiving an actuating plunger 4|. This plunger is formed with a shoulder 42 for limiting outward travel of the plunger. The plunger extends across the interior of the housing and is provided with a stem 43 which is received in a recess 44 formed in the housing member 9. The plunger is also provided with an enlarged portion 45 which receives the lower end of a coil spring 46, the upper end of which bears against the arm 41 of the bell crank lever 32. If desired, the enlarged portion 45 may be made adjustable on the plunger, as by screw threads, so as to provide for adjustment of the initial tension of the coil spring 46.

With the parts in the positions shown, the plunger 4| is in its depressed position, which has placed suii'icient tension on the spring 48 to force the armature 33 away from the permanent magnet, thus causing the movable contacts to be disengaged from the stationary contacts. As the plunger 4| recedes, the tension on spring 48 will be eventually reduced to the point at which it is insuflicient to overcome the pull of the permanent magnet. When this occurs, the bell crank lever will rotate counter-clockwise as shown in Fig. 4, this motion taking place with a snap action so that the movable contacts are snapped into engagement with the stationary contacts. When the plunger is depressed, the tension on the spring 46 will be gradually increased until it overcomes the attractive force of the magnet. When this occurs, the contacts will open with snap action.

In order to adjust the gap between the armature and magnet when the contacts are closed, the stationary contact studs are formed with hollow sockets 49. This permits the studs to be turned by a wrench which is inserted through openings 48 in the housing which are in alignment with the studs. This arrangement provides for adjusting the switch after it has been completely assembled.

It should be noted that with the angular terminal panel, the panel become accessible from two The construction in which an elongated plunger extends completely across the housing insures that the plunger will not be cocked in operation. In the prior art switches, employing short floating plungers. the plunger can be canted or tilted relative to its slide by the actuator, thereby increasing the friction between the plunger and its guide. The elongated plunger construction provided by the present invention insures that no such canting or tilting can occur and thus increases the sensitivity of the switch.

From the foregoing it will be seen that the present invention provides a simple and compact snap switch mechanism having a terminal panel which is accessible in a large variety of applications of the switch in a control device. While I have shown and described a preferred form of the invention, it is obvious that many changes in construction may be made without departing from the spirit and scope of the invention. It is therefore desired to be limited only by the scope of the appended claims.

What is claimed is:

1. An enclosed snap switch comprising a generally rectangular housing, a stationary contact mounted within said housing, a magnet disposed within said housing in proximity to a wall thereof, a movable contact mounted within said housing for coaction with said stationary contact, a bracket mounted within said housing and including an ear providing a pivot mounting and an extended portion engaging and retainably positioning said magnet against said wall, and a bell crank lever supported by said pivot and having arms embracing an angle, one of said arms having a movable contact facing outwardly with respect to said angle, said lever including an armature part disposed in adjacent operative relation with respect to said magnet and an actuator disposed within said angle and positioned to move said crank in contact movements.

2. An enclosed snap switch comprising a generally rectangular apertured housin including an outer wall portion disposed in obtuse angle forming relation with respect to a pair of spaced walls joined therewith, a pair of terminals mounted in spaced relation on said wall portion, a pair of stationary internal contacts carried by one of said'pair of walls in adjacent relation to and connected with said pair of terminals, a magnet disposed between said stationary contacts and adjacentsaid one wall, a bracket detachably secured to said wall portion and including a first inwardly oil-set part afiording a pivot mounting and a second inwardly off-set part engaging and retainably positioning said magnet against said one wall, a bell crank supported by said pivot mounting and including an armature arm disposed in adjacent operative relation with respect to said magnet, a contact bar carried by said armature arm in bridgable relation with respect to said stationary contacts; and means guided through the apertures of said housing for actuating said lever so as to move said armature arm toward or away from said magnet.

3. An enclosed snap switch comprising a generally rectangular housing including an outer wall portion disposed in obtuse angle forming relation with respect to a pair of spaced walls joined therewith, a pair of terminals mounted in spaced relation on said wall portion, a pairv includinganomaimreanndisposedinadjaoent' operative relation with respect to said magnet and asecond arm disposed in spaced relation and with respect to a wall oi said housing 'epaeedlysaidotherwmsaidopposed wallshavingapairoiopcnings thereindlspoeed in general alingment with respect to each other. acontactharcaniedhysaidarmatmeamin hridgable relation with respect to said stationary contacts, a plunger type actuator having opposite end portions 7 in said for guided reciprocation therein with one or said end portions accessible for actuation, and resilient motion transmitting means disposed with the angle oi the bell crank operatively connecting an intermediate portion oi said achietor with said second lever arm.

4. An enclosed snap switch comprising a genorally rectangular housing, a stationary contact mounted on one wall said housing, a movahle contact mounted within said housing for coaction with said stationery contact. a bracket mounted within said housing and including a part providing a pivot mounting, a hell crank supported by said pivot mounting and including a first ann connected in actuating relation with respect to saidmovahle contact ende secondurm W housingondtheaperturedhellcrank hetween'twowallsoi'saidhmrsingin spaced relation thereto and atrlxht anglesto the wall provided with the stationary t. an elongated actuator extending hetween and carried by opposed portions o1 said two walls lorguided reciprocationin adlreetiongenemlly perpendicular with respect to said second lever em, and resilient motion irlnsmitting means operatively eonnectingan intermediate portion oi said aehrator with cold second lever um.

5. A switchinciudingohousinghavlngocontactnremhenamagnetendahracketeloeelyodjacent one another andtoihehoulim. abelicrankplvotailymountedonthemt, eeidcrankhavinganmsemhracinganangleaw Ioomsnidconhctmagnetandhmckchacmtact camedhyoneannoiihem-ankini to the contact on the and an actuator otherem.

o. A switch including an apertured housing having a contact member, a magnet and a bracket therewithin, a bell crank pivotally mounted on the bracket, said crank having armsemhracing 5 ananglesumcientlvsmalltopermitaswinging movement oi the crank about its pivotal mountlrm on the bracket, a contact carried by one arm oi the crank in iuxtaposiflon to theicontact on the an actuator receivable i'or guided with respect to the other of said pair of walls movement in the apertures in the housing and provided with a shoulder for engagement with the other arm of the crank to cause contact en 8 8mg motion of the crank.

i v 17. A including a housing apertured at spaced poinie and having contact lever and a bracket, in crank pivotaily mounted on the bracket, said crank having one apertured arm endonecontactarmanactuatorextending ilmough the apertures in said housing to he guided thereby, said actuator being shouldered and extended through the aperture in the housin: and through said hell crank arm. and resilient means between the shoulder and the said apertured arm.

s. or switch including on We housing having spaced lined contacts and a magnet therehetween a bracket for said housing spaced irom said magnet and provided with a pivotal mountin a hell crank pivotally secured to said bracket endprovldedwithonarmannearmandanawtuned actuator arm. eaidarms being disposed at an angle embracing an actuator and a contact contact her. and a shouldered actuator extendingrjeciprocahlyintoflreapemrresinthe mm with a ehoulder inoperative relation to said Thei'ollowingreierencesareoi'recordinthe iile oi this'patent:

Certificate of Correction Patent No. 2,460,837. February 8, 1949.

HOMER E. MALONE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 71, for the word become read becomes; column 5, line 22, claim 3, for with read within; 7 and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 21st day of June, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uomnz'asioner of Patents. 

